1. Field of the Invention
This invention relates generally to dispensing closure caps for containers, and more particularly to an adjustable dispensing closure cap having more than one dispensing position which provides venting of any excess pressure which may build up within the container when the closure is in a fully closed position.
2. Description of the Related Art
Dispensing closure caps for containers typically are of the push-pull or threaded screw type and include a fully open dispensing position, a fully closed position and one or more intermediate dispensing positions. An example of such a closure is illustrated in U.S. Pat. No. 4,967,941 which is assigned to the same assignee as the assignee herein. That patent discloses a variable dispensing closure which provides positive indication of the cap position during manipulation.
During shipping, handling, storage and use of the container, excess pressure can build up within the container when the closure is in a fully closed position. Such pressure build up typically is dependent on the material within the container and the conditions which the container is subjected to during storage and handling. If excess pressure is allowed to accumulate, the container may rupture or distort, the cap may be dislodged from the container or the contents may explode outward upon initial opening of the cap.
Additionally, it frequently is desirable to heat container contents within the container prior to use, such as cheese sauce products or ice cream topping, for example. Heating typically is accomplished with a microwave oven, boiling water or any similar method. Heating can cause excess pressure to develop and build up within the container which must be vented for the reasons given above.
Existing closures which provide venting typically are utilized with squeeze bottles. These bottles are opened to dispense container contents by squeezing the bottle to increase the pressure within the bottle and open a discharge valve. When released, the bottle expands to close the discharge valve and simultaneously open a separate vent valve to admit outside air into the bottle to replenish the amount of product dispensed.
An example of such a closure and squeeze bottle is illustrated in U.S. Pat. No. 4,506,809 which discloses a combined product discharge and air vent passage controlled by a diaphragm valve. Such a closure, however, does not provide for venting of any excess interior pressure when the closure is in the fully closed position. Additionally, such a closure is very complex in design, is difficult and expensive to manufacture, particularly in a molding process, and can be too fragile to be used repeatedly without failure.
It therefore is desirable to provide a variable dispensing closure cap which provides venting of pressure from within a container in a fully closed position, is simple in design, can readily be molded with a minimum number of parts and is sturdy in construction for repeated use without failure.